234 ‘on varieties of domestic animals. Oct. 16. 
there were a male and a female pure white, there. is 
little room to doubt but a breed of white mice, might 
have been procreated, if these had been fhut up to- 
gether. IT was at that time so much hurt by the ra- 
vages of mice, that I was glad to get them all de- 
stroyed, so that mo experiment was made of it ; I 
have since regretted it was not done; and this fhows 
exactly what may be expected to be done among do- 
“mestic animals, and what does actually happen among 
wild animals, in cases of this kind. Probably no 
marks of tde white black bird, or of the pied rook, 
“were preserved among the progeny, or they would be 
soon absorbed in the general mafs. ! 
Another circumstance that may occasion a diver- 
sity among domestic animals, which has not been 
much attended to, though individuals must have, on 
many occasions, remarked it is, that though the 
family likenefs, if you please, or the distinguifhing 
peculiarity of the breed, will sometimes be totally 
wanting in owe individual of the breed, yet there is a 
tendency to revert to it; and it will often happen 
that the progeny of that accidental* variety, will re- 
semble the parent stock more than the immediate pa- 
yent himself. A man, for example, who, from a casu- 
al individual deviation, bears no resemblance to his 
father, may have a child that is the exact picture of 
its grandfather. In like manner a horse, which has 
been casually black, though descended from a breed, 
the general colour of which is white or grey, may 
%* We call accidental such citcumstances as we capfiot account for 
in matters of this sorte 
Se 
